By MyHealthNewsDaily Staff

Most people who have sinus infections should not be treated with antibiotics because the drugs are unlikely to help, according to new guidelines from infectious disease experts.

Although sinus infections are the fifth-leading reason for antibiotic prescriptions, 90 to 98 percent of cases are caused by viruses, which are not affected by antibiotics, according to the guidelines issued today (March 21) by the Infectious Diseases Society of America. Used inappropriately, antibiotics spur the development of drug-resistant superbugs, the IDSA says.

"There is no simple test that will easily and quickly determine whether a sinus infection is viral or bacterial, so many physicians prescribe antibiotics 'just in case,'" said Dr. Anthony Chow, professor emeritus of infectious diseases at the University of British Columbia, Vancouver and chairman of the guidelines panel.

"However, if the infection turns out to be viral — as most are — the antibiotics won't help and in fact can cause harm by increasing antibiotic resistance, exposing patients to drug side effects unnecessarily and adding cost," Chow said.

A study of 166 people with sinus infections published in February in the Journal of the American Medical association showed that those who took antibiotics saw no better improvement in their symptoms than those taking a placebo.

The new guidelines provide specific characteristics of the illness to help doctors distinguish between viral and bacterial sinus infections.

How to tell if it's bacterial
A sinus infection, properly called acute rhinosinusitis, is inflammation of the nasal and sinus passages that can cause uncomfortable pressure on either side of the nose, and last for weeks. Most sinus infections develop during or after a cold or other upper respiratory infection, but other factors such as allergens and environmental irritants may play a role.

According to the guidelines, a sinus infection is likely caused by bacteria, and should be treated with antibiotics, if any of these criteria are met:

• symptoms last for 10 days or more and are not improving (previous guidelines suggested waiting seven days)
• symptoms are severe, including fever of 102 degrees Fahrenheit or higher, nasal discharge and facial pain lasting three to four days in a row
• symptoms get worse, with new fever, headache or increased nasal discharge

For adults, 5 to 7 days is enough
The guidelines recommend treating bacterial sinus infections with amoxicillin-clavulanate, instead of the drug currently used, amoxicillin, because the addition of clavulanate helps to thwart the development of antibiotic resistance. The guidelines also recommend against using other commonly used antibiotics, due to increasing drug resistance.

While previous guidelines have recommended taking antibiotics for 10 days to two weeks, the new guidelines suggest five to seven days of antibiotics is long enough for the treatment of adults, and will not encourage bacterial resistance. The IDSA guidelines still recommend children receive antibiotic treatment for 10 days to two weeks.

Whether a sinus infection is bacterial or viral, decongestants and antihistamines are not helpful and may make symptoms worse, the guidelines say.

The voluntary guidelines are not intended to take the place of a doctor's judgment, but rather support the decision-making process, which must be made according to each patient's circumstances, the IDSA says.

The guidelines will be published in the April 15 issue of the journal Clinical Infectious Diseases.

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